1. Field of the Invention
The present invention relates to a wireless communication system. More particularly, the present invention relates to a method and apparatus for controlling Short Message Service (SMS) delivery to a User Equipment (UE) over a Packet-Switched (PS) network without involvement of any Circuit Switched (CS) network node.
2. Description of the Related Art
Mobile communication systems developed to provide the subscribers with voice communication services on the move. With the rapid advance of technologies, the mobile communication systems have evolved to support high speed data communication services as well as the standard voice communication services. However, the limited resource and user requirements for higher speed services in the current mobile communication system spur the evolution to more advanced mobile communication systems.
Meanwhile, the Short Message Service (SMS) has been provided in Circuit Switched (CS) domain. FIG. 1 shows an exemplary procedure for delivering Mobile Terminating (MT) SMS to the User Equipment (UE) in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) system.
FIG. 1 is a diagram illustrating an SMS transmission procedure under assistance of CS network in a system according to the related art.
Referring to FIG. 1, the SMS message that arrived at an SMS-Service Center (SMS-SC) 110 is transferred to the SMS Gateway Mobile Switching Center (SMS-GMSC) 120 at step S101.
If the SMS message is received, the SMS-GMSC 120 requests the Home Location Register (HLR) 130 for routing information with the recipient address at step S103.
The HLR 130 searches its database for the corresponding recipient address to notify the SMS-GMSC of the address of the Visitor Location Register (VLR) 140 to which the UE having the recipient address belongs at step S103. The SMS-GMSC 120 checks the address of the VLR to which the UE belongs and forwards the SMS message to the corresponding VLR 140 identified by the VLR address at step S105.
Upon receipt of the SMS message, the VLR 140 forwards the SMS message to the MME 150 at step S107. At this time, the recipient ID (i.e., Mobile Station International ISDN Number (MSISDN)) of the SMS message is converted to a Temporary Mobile Subscriber Identity (TMSI) as a temporary ID for use in a CS network.
The Mobility Management Entity (MME) 150 retrieves the SAE-Temporary Mobile Subscriber Identity (S-TMSI) as an ID for use in the PS network from the TMSI and transports the SMS message to the UE 170 identified by the S-TMSI via the evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (E-UTRAN) 160 at step S109.
Meanwhile, Long Term Evolution (LTE) is a network optimized for PS data transmission and thus it is typical for the UE to perform attach/registration to the PS network. In the system of FIG. 1, however, it is shown that the UE attached to the PS network has to use the VLR/MCS 140 as a CS network node for SMS transmission.
The network operators adopted LTE for providing the smartphone users with data-centric services and the service providers providing voice call service over the LTE network (i.e., Voice over IP (VoIP)) rather than the CS network, it can be a significant burden to maintain and manage the CS network nodes such as VLR/MSC 140 only for providing the SMS service.
There is therefore a need of a study on the function for providing the subscribers with SMS over PS network without the MSC 140 (i.e., CS infrastructure).
Therefore, a need exists for a method and apparatus for controlling Short Message Service (SMS) delivery to a User Equipment (UE) over a Packet-Switched (PS) network without involvement of any Circuit Switched (CS) network node.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.